Apparatus for guiding a textile tow



Feb. 1, 1966 s. F. CHADWICK 3,231,958

APPARATUS FOR GUIDING A TEXTILE TOW Filed Jan. 20, 1964 FIG. FIG-4IVAIIIV,

. INVENTOR STEPHEN FRANCIS CHADWICK ATTORNEY APPARATUS FOR GUIDING ATEXTILE TOW Stephen Francis Chadwick, Camden, S.C., assiguor to- E. I.du Pont de Nemours and Company, Wilmington,

Deb, a corporation of Delaware Filed Jan. 20, 1964, Ser, No..33 8,878 3Claims." (Cl. 28-1) This invention relates to theproduc'tion ofsynthetic fibers, and is particularly concerned with'that phase of fiberproduction which involves the formation of tow preparatory to crimpingof the fibers.

A tow is a ropeor ribbon of fibers with'a denier in the hundreds ofthousands, The tow in the form of a ribbon is usuallycrimpe'd'by'passage through a stutlerbox crimper-as-describedin U.S.Patents2,311, 174 and through the nip of two feed rolls under very highpressure. These feed rolls'force theribboh of-fibers' into a confinedspace where its movement is restricted by a clapper plate which opposesthe exit of the fibers from the chamber. Because of the large mass offibers and the high nip pressures necessary to force the fibers throughthe stutter-box, crimping is a critical operation where fiber damage canoccur. If the thickness of the ribbon varies, either from side to sideor lengthwise, then crimping will also vary. Thick areas of the tow maybe damaged by the excess pressure of the feed rolls. Thin areas in thetow may not be fully crimped. Poorly crimped areas may cause splittingof the tow, which will interfere with subsequent operations in which thetow is converted to yarns and fabrics.

It is an object of the present invention to provide apparatus for moreaccurately controlling the thickness of the tow ribbon prior tocrimping. Other objects and achievements will appear from thedescription which fol-,

lows.

The control of tow structure throughout its width by carefully puttingit together from a number of narrower ribbons, which in turn. may havereceived mechanical treatments to make their cross sections essentiallyuniform, has been the subject of recent investigations and of novelapparatus designs. instance, forms the subject matter. of copendingapplication of John Charles Resor, Ser. No. 244,443 (filed December 13,1962), now US. Patent No. 3,145,429. Residual problems neverthelessexist, and the improved tow thus obtained generally has a sort ofpancake cross section. That is, it is of essentially uniform crosssection throughout nearly its entire width, but it thins out at theedges. p

In a further copending application (Walter H. Hendrix, Ser. No. 291,069,filed June 27, 1963), the improvement is suggested of passing the towover a slightly staggered pair of flanged spools. Such spools, if theyare slightly narrower than the tow fed through them, cause the edges tofold over upon themselves, thereby making the thickness of the tow atthe edges more nearly the same as that throughout its width. However,there is no control over the direction of turning, and the two edges maysometimes be turned onto the same face of the tow and sometimes ontoopposite faces.

The present invention is an improvement upon Hendrix and is intended foruse in conjunction with his apparatus whereby to further improve the netresult.

I have found that in folding the edges of tow prior to crimping,superior results are frequently obtained if the edges are turned inopposite directions; that is, if one edge is turned up onto the upperface of a horizontally moving tow, while the other edge is turned downunder the underside of the tow. In other words, the entire foldingprocess is made to follow an S-shaped configuration.

To achieve this result, this invention interposes a novel 2,747,233] Inthisoperation' the *ribbon first passes a appar'atus along the lineoftow movement just prior to its passage through the spool-shaped formerpair of Hendrix. The novel apparatus of this'invention comprises a basefrom which rise twoparalleledge" guides in" a plane-essentially atrightangles-to theline of movement of the-tow. But these edge-guides 'donot rise perpendic-' ularly to the base; instead,-theyare both inclinedsideways in the same direction at an angle of about 45? totheplane ofthe passing town The'inner faces of the two edge guides are spacedapartat a distance whichwill cause the passing tow to contact andconstrain the latter,- whereby to turn slightly one edge 'of the towtoward the base of the guide and the other edge away from the base. Therest of thebendin'g of each-edge upon the faceofithe tow is achieved bya pair ofspools,as in the arrangement of Hendrix, the apparatus of the"instant invention se'rving' merely to predispose the two edges forbendingun op .po's'ite directions, whereby the desired S-shaped 'configuration will be assured:

For further details, reference is now made to the accomapnying drawing,in which:

FIG. 1 is a top view of the novel channel type apparatus of thisinvention.

One such improvement, for

FIG. 2 is a section of FIG. 1 along line 2-2.

FIG. 3 is a front view of one of the spool shaped formers used inconjunction with the basic apparatus of this invention.

FIG. 4 is a diagrammatic representation of an apparatus layout in whichtow is passed first through the predisposing channel of this invention,then through a pair of spool shaped formers of the Hendrix type andfinally into the nip rolls of a conventional crimper. FIG. 5 is asection through a tow made up of two layers of partially overlappingribbons, and whose edges have been bent inwards by an apparatus layoutas shown in FIG. 3.

Now, referring to FIG. 1, 1, 1 represent parallel bars or edge guidesrising from a base 2 which is attached to a support 9 (FIG. 4) by theaid of a notch and screw device 3. 4 is a cross section of the tow, withthe ends 5 and 6 being displaced in opposite directions by the parallelguide bars. 12, 12 are ceramic liners for bars 1, 1 to give themimproved abrasion resistance.

In FIG. 4, the novel channel unit of this invention is partly insection. So, the top member shows one of the parallel bars 1 in thebackground with the tow passing in front of it. 7, 7 are two flangedspools as in the Hendrix application. 8, 8 are the feed rolls of thestuffing box crimper 10.

FIG.-5 illustrates the advantage of folding the edges 42, 42 back onopposite sides of the tow 4. The ribbons 41 in each layer of the towoverlap, but the bottom layer is staggered with respect to the top layerto avoid piling up the overlaps on top of each other. The result is thatinitially, the tow is only one layer thick at the extreme edges. Curlingback the edges in opposite directions as shown at 42, 42, assures auniform thickness for the tow essentially throughout its width.

The edge guides 1, 1 may have considerable extent in the direction ofthe tow motion or they may be no larger in this dimension than in theirwidth crosswise of the line of tow, inasmuch as usually the apparatus ofthis invention will be placed sufiiciently close to the flanged pair ofspools, that relaxation and straightening out of the tow widthwise willnot occur.

It will be understood that the other details of this invention maylikewise be varied widely, within the skill of those engaged in thisart.

I claim as my invention:

1. As an element in an apparatus for guiding a moving textile tow, anedge-turning channel situated in the path Patented Feb. 1, 1966 of themoving tow, said channel having a base portion and essentially paralleledge-guides rising from said base portion at an angle of about 45 to theplane of the moving tow in the dimension transverse to the tow motion,the inner faces of said edge guides being spaced apart at a distancewhich will cause said parallel edge guides to contact and constrain themoving tow, whereby one of said edge guides will turn theedge of the towwhich it contacts toward one face of said tow while the other edge guidewill turn its edge of the tow in the oposite direction.

2. An element as in claim 1, said parallel edge guides being lined withceramic material along the faces which make contact with the movingfibers.

3. Apparatus for shaping the cross section of a moving tow ofessentially parallel, discrete, continuous textile filaments, whereby toproduce a tow of essentially uniform thickness throughout its breadth,which comprises a spoolshaped former situated in the path of the movingtow and having its flanges spaced apart a distance essentially equal tothe desired final width of the tow, and an edge-turning channel situatedin the path of the moving tow before it comes in contact with saidspool-shaped former, said edge-turning channel having a base portion andessentially parallel edge guides rising from said base portion at anangle of about 45 to the plane of the moving tow in the dimensiontransverse to the tow motion, said edge guides being spaced apart at adistance which will cause said parallel edge guides to contact andconstrain the moving tow and whereby one of said edge guides will turnthe edge of the tow which it contacts toward one face of said tow whilethe other edge guide will turn its edge of the tow in the oppositedirection, thereby predisposing the tow to have its thin edges foldedupon themselves in S-shaped fashion as the tow subsequently passesthrough said spool-shaped former.

References Cited by the Examiner UNITED STATES PATENTS DONALD W. PARKER,Primary Examiner.

1. AS AN ELEMENT IN AN APPARATUS FOR GUIDING A MOVING TEXTILE TOW, ANEDGE-TURNING CHANNEL SITUATED IN THE PATH OF THE MOVING TOW, SAIDCHANNEL HAVING A BASE PORTION AND ESSSENTIALLY PARALLEL EDGE-GUIDINGRISING FROM SAID BASE PORTION AT AN ANGLE OF ABOUT 45* TO THE PLANE OFTHE MOVING TOW IN THE DIMENSION TRANSVERSE TO THE TOW MOTION, THE INNERFACES OF SAID EDGE GUIDES BEING SPACED APART AT A DISTANCE WHICH WILLCAUSE SAID PARALLEL EDGE GUIDES TO CONTACT AND CONSTRAIN THE MOVING TOW,WHEREBY ONE OF SAID EDGE GUIDES WILL TURN THE EDGE OF THE TOW WHICH ITCONTACTS TOWARD ONE FACE OF SAID TOW WHILE THE OTHER EDGE GUIDE WILLTURN ITS EDGE OF THE TOW IN THE OPOSITE DIRECTION.